It is much larger than any other North American clubtail, at 3.3 inches, with black and yellow markings and green eyes. Males can be distinguished at a distance by their habit of curling their abdomens under while flying, forming a sideways J shape. The nymph is unusual, with a very flat, wide body. It is slow-moving and lives among bark and leaf litter at the edges of streams, where its dark color provides camouflage.
Found near ponds and streams, slow moving water.